The broad goal of the proposed research is to further basic knowledge about psychological and physiological processes involved in the voluntary control of human physiological functions by mean of biofeedback techniques. More specifically, the objective is to evaluate the potential of biofeedback techniques in the control of physiological and subjective reactions to stressful stimuli. Studies are proposed on the effects of biofeedback on heart rate changes and subjective reactions to the cold pressor test (immersion of the hand in ice water). Associated physiological, cognitive, and individual differences will be examined. Instructional and feedback influences will be compared. Comparison will also be made of the effects of feedback for different physiological functions (electrodermal activity, systolic blood pressure) and of the effects of other behavioral methods (paced respiration, relaxation, cognitive self-statements). The project will also determine whether training in the control of heart rate by means of biofeedback training produces effects on performance and self-report in non-noxious stimulus conditions. Normal volunteers are studied in controlled laboratory experiments of one or more sessions. The experiments are run by a digital computer (PDP-11/GT-40 System) which controls experimental events, creates biofeedback displays, stores and analyzes data. Physiological measures include blood pressure, heart rate, skin conductance, respiration, electromyographic activity, finger pulse and blood volume, and skin temperature. Questionnaires and rating scales are used to assess perceptions of the stressor, individual differences in autonomic awareness, and other variables. This research has implications for mechanisms involved in voluntary control of physiological responses and how it varies under stress and non-stress conditions, for the psychophysiology of "emotion," and for the management of anxiety and pain.